base/test/mock_time_provider.h

   1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 // TODO(akalin): Change all users of this class to use SimpleTestClock
   6 // or SimpleTestTickClock and remove this class.
   7
   8 // A helper class used to mock out calls to the static method base::Time::Now.
   9 //
  10 // Example usage:
  11 //
  12 // typedef base::Time(TimeProvider)();
  13 // class StopWatch {
  14 //  public:
  15 //   StopWatch(TimeProvider* time_provider);
  16 //   void Start();
  17 //   base::TimeDelta Stop();
  18 //  private:
  19 //   TimeProvider* time_provider_;
  20 //   ...
  21 // }
  22 //
  23 // Normally, you would instantiate a StopWatch with the real Now function:
  24 //
  25 // StopWatch watch(&base::Time::Now);
  26 //
  27 // But when testing, you want to instantiate it with
  28 // MockTimeProvider::StaticNow, which calls an internally mocked out member.
  29 // This allows you to set expectations on the Now method. For example:
  30 //
  31 // TEST_F(StopWatchTest, BasicTest) {
  32 //   InSequence s;
  33 //   StrictMock<MockTimeProvider> mock_time;
  34 //   EXPECT_CALL(mock_time, Now())
  35 //       .WillOnce(Return(Time::FromDoubleT(4)));
  36 //   EXPECT_CALL(mock_time, Now())
  37 //       .WillOnce(Return(Time::FromDoubleT(10)));
  38 //
  39 //   StopWatch sw(&MockTimeProvider::StaticNow);
  40 //   sw.Start();  // First call to Now.
  41 //   TimeDelta elapsed = sw.stop();  // Second call to Now.
  42 //   ASSERT_EQ(elapsed, TimeDelta::FromSeconds(6));
  43 // }
  44
  45 #ifndef BASE_TEST_MOCK_TIME_PROVIDER_H_
  46 #define BASE_TEST_MOCK_TIME_PROVIDER_H_
  47
  48 #include "base/time/time.h"
  49 #include "testing/gmock/include/gmock/gmock.h"
  50
  51 namespace base {
  52
  53 class MockTimeProvider {
  54  public:
  55   MockTimeProvider();
  56   ~MockTimeProvider();
  57
  58   MOCK_METHOD0(Now, Time());
  59
  60   static Time StaticNow();
  61
  62  private:
  63   static MockTimeProvider* instance_;
  64   DISALLOW_COPY_AND_ASSIGN(MockTimeProvider);
  65 };
  66
  67 }  // namespace base
  68
  69 #endif  // BASE_TEST_MOCK_TIME_PROVIDER_H_